Coercive fields of amorphous Co–Si films with diluted arrays of antidots

Abstract

Diluted arrays of antidots have been patterned by electron beam lithography and an etching process on amorphous Co–Si films of well defined uniaxial anisotropy. The analysis of the angular dependence of the hysteresis loops shows that the antidot arrays present a similar uniaxial anisotropy to the unpatterned film, and that the main effect of patterning for this small antidot density appears as an enhancement in the coercivity. The observed easy axis coercive fields are consistent with the estimates for domain wall pinning by a non-magnetic inclusion surrounded by a closure domain structure. However, the angular dependence of the coercivity presents an anomalous behaviour that points to the existence of an anisotropic domain wall pinning mechanism of the antidot arrays.